No magic, just a fan replacement with temperature-dependent speed control. Fractal Design Silent Series R3 50mm fan is an exact fit for screw holes, and just replacing the original fan with this will probably be sufficient for many. I also did speed control based on 8-pin AVR chip that has internal temperature sensor, see http://www.nomad.ee/micros/rigol_fan/index.shtml for details.

It would be interesting to know if there is a temperature raise after the fan replacement, and by how much.By any chance, did you happen to measure the temperatures inside the case (before and after the replacement)?

It certainly gets warmer, simply beacuse there is less airflow and the way the internals of the scope are built it relies fully on forced air cooling. I did not measure the internal temperature before or after the hack. It gets warm but not hot.

Cool, I like the idea of the external temps control. I am not sure where the DS1000Z takes its temp from. Is that ambient/exhaust or it's on a specific chip/radiator?I am worried that just watching exhaust temperature will still allow some component to run too hot.

Have a question here, don't you have to consider the temperature of key components rather then the inside air temperature? Without sufficient air flow, there can be dead air spaces where component overheat because of lower temperature diferencine of component and air? Isn't this why manufacturers place temp. sensors on key heatsinks?

Heat sinks on individual components are calculated for maximum allowed junction temperature in a certain ambient temperature. If the ambient is higher than a value used in calculations, the die will potentially run hotter than intended. The safety margin used in the calculations is a lot wider than few degrees ambient temperature rise, though. In my case, as the fan speed is temperature controlled the system will settle on some equilibrium point where the fan runs at sufficient speed to prevent further ambient temperature rise. As long as this point is reached at lower than maximum fan speed, the temperature is kept under control. If this point would seem too high, then changing the temperature/speed relationship is just a microcontroller firmware change. After running the scope for many hours and looking at how long it takes for the temperature to even get up to the point where fan starts I don't think the mod will cause any problems.

I'm wondering if they designed it with a fixed fan speed to help prevent calibration drift. Did you check if the calibration drifts based the amount of airflow?

I don't know about the DS1000Z series, but my DS2000A shows a large DC offset over 1mV immediately after power on cold and it takes 30 minutes to stabilize down to zero offset, then it's pretty much stable for hours.

So a temperature controlled fan like yours could help reach the calibration temperature much faster, but on the other hand, it could cause temperature to vary wildly for the components directly in the path of the fan airflow.

I'm wondering if they designed it with a fixed fan speed to help prevent calibration drift. Did you check if the calibration drifts based the amount of airflow?

I don't know about the DS1000Z series, but my DS2000A shows a large DC offset over 1mV immediately after power on cold and it takes 30 minutes to stabilize down to zero offset, then it's pretty much stable for hours.

So a temperature controlled fan like yours could help reach the calibration temperature much faster, but on the other hand, it could cause temperature to vary wildly for the components directly in the path of the fan airflow.